Direct liquid phase synthesis of ordered L10 FePt colloidal particles with high coercivity using an Au nanoparticle seeding approach†
Abstract
Ordered L10 and high coercivity FePt nanoparticles were successfully synthesized via a chemical method using pre-synthesized Au nanoparticles as nuclei seeds. The size of the Au nanoparticles seems to play a significant role in the formation of the tetragonal phase (L10) FePt colloidal nanoalloys. Seeding with ∼12 nm diameter monodispersed Au nanoparticles in the reaction mixture was found to lead to partial L10 FePt particles with 2.8 kOe coercivity at room temperature, while seeding with ∼6 nm Au nanoparticles leads to the formation of well L10 ordered FePt colloidal particles with 8.8 kOe coercivity at room temperature, one of the highest values for the direct liquid phase synthesis of L10 FePt colloidal particles. Furthermore, seeding with smaller Au particles decreases the ordering temperature from 360 °C to 300 °C leading to the formation of more uniform well-shaped nanoparticles.